#include "mystdio.h"
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

mFILE* mfopen(const char* filename,const char* mode)
{
    int fd=-1;
    if(strcmp(mode,"r")==0)
    {
        fd=open(filename,O_RDONLY);
    }
    else if(strcmp(mode,"w")==0)
    {
        fd=open(filename,O_WRONLY | O_CREAT | O_TRUNC,0666);
    }
    else if(strcmp(mode,"a"))
    {
        fd=open(filename, O_CREAT| O_WRONLY | O_APPEND,0666);
    }

    if(fd<0) return NULL;
    mFILE* mf=(mFILE*)malloc(sizeof(mFILE));
    if(!mf)
    {
        close(fd);
        return NULL;
    }

    mf->fileno=fd;
    mf->flag=FLUSH_LINE;
    mf->size=0;
    mf->cap=SIZE;

    return mf;
}

void mfflush(mFILE* stream)
{
    if(stream->size>0)
    {
        //写到内核文件的文件缓冲区中
        write(stream->fileno,stream->outbuffer,stream->size);
        //刷新到外设
        fsync(stream->fileno);
        stream->size=0;
    }
}
int mfwrite(const void*ptr,int num,mFILE* stream)
{
    //1.拷贝
    memcpy(stream->outbuffer+stream->size,ptr,num);
    stream->size+=num;

    //检测是否要刷新
    if(stream->flag==FLUSH_LINE && stream->size>0 && stream->outbuffer[stream->size-1]=='\n')
    {
        mfflush(stream);
    }

    return num;
}
void mfclose(mFILE* stream)
{
    if(stream->size>0)
    {
        mfflush(stream);
    }
    close(stream->fileno);
}
